Light sensitive photothermographic film is used in many applications ranging from a standard photocopying apparatus to graphic arts and/or medical imaging systems. For example, laser imagers are widely used in the medical imaging field to produce visual representations on film of digital image data generated by magnetic resonance (MR), computer tomography (CT) or other types of scanners. Laser imagers typically include some type of film supply system, a film exposure system, a film processing system, and a transport system that moves film from the supply system along a transport path through the laser imager. Sheets of unexposed film are typically stacked within a standardized cartridge or magazine which is inserted into the laser imager. The supply system generally includes a mechanism for removing and providing sheets of unexposed film from the cartridge to the transport system for subsequent transport through the exposure and processing systems and delivery of a developed image to a dispensing area for access by a user.
When removing sheets of film from the cartridge, it is important that the supply system remove and provide only one sheet of film at a time from the cartridge to the transport system. Providing more than one sheet of film to the transport system can cause film jams along the transport path and result in poorly and/or improperly developed images requiring re-development, both of which result in lost productivity and potential damage to the imager. Unfortunately, due to a variety of factors such as, for example, static electricity, film coatings, and vacuum-like effects between sheets, sheets of photothermographic film tend to cling or stick together when placed in a stack, making removal of individual sheets of film from the stack difficult. In fact, when trying to lift/remove a top sheet of film from a stack, the attraction between the sheets of film is so strong that sometimes the entire stack clings to and is lifted with the top sheet.
One type of film supply system includes a rotatable pickup head that employs suction cups to engage the top sheet of film of the stack. After the suction cups create a vacuum seal with the top sheet of film, the pickup head is rotated back and forth between one or more positions to flex the film so as to separate the top sheet of film from the other sheets of the stack. While this system is generally effective at removing the bulk of the lower sheets of the stack from the upper sheets of the stack, it is not always effective at separating the upper sheets of film from another, such as the one or more sheets immediately below the top sheet in the stack. An example of such a system is described by U.S. Patent Publication No. 2004/0169325 A1 to Nelson, filed on Feb. 28, 2003, which is assigned to the same assignee as the present invention, and is herein incorporated by reference.
As such, there is a need for an improved system for separating individual sheets of film from a stack of film of a film source of an imaging apparatus.